What does dry contact mean?
In the field of electrical engineering and automation control, "dry contact" is a common professional term, but it may be unfamiliar to non-professionals. This article will combine the hot topics and hot content on the Internet in the past 10 days to explain in detail the definition, application scenarios and differences between dry contacts and other contacts, and help readers better understand this concept through structured data.
1. Definition of dry contact

Dry Contact, also known as passive contact, refers to a switch contact without power supply. Its characteristic is that the contact itself does not provide voltage or current, but only serves as an on-off device for switching signals. There are only two states of dry contact: "open" and "off", which are completely dependent on the switching of the external circuit.
2. The difference between dry contacts and wet contacts
To better understand dry contacts, we can compare them with wet contacts:
| Comparative item | dry contact | wet contact |
|---|---|---|
| power supply | Without power supply | With power supply |
| Signal type | switch signal | voltage or current signal |
| Application scenarios | Relays, sensors, alarm systems | PLC input, analog control |
3. Application scenarios of dry contacts
Dry contacts are widely used in the following fields:
1.Relay control: Dry contacts are often used at the output end of relays to control the on and off of other equipment.
2.sensor signal: Some sensors (such as door sensors and temperature switches) output signals through dry contacts.
3.alarm system: Fire alarms, security systems, etc. often use dry contacts to transmit switch signals.
4.Industrial automation: Control systems such as PLC and DCS receive the switching status of external equipment through dry contacts.
4. Advantages of dry contacts
1.High security: Since the dry contact is not electrified, the risk of short circuit or electric shock is avoided.
2.Strong compatibility: Dry contacts can be used with circuits of different voltage levels, without worrying about power matching issues.
3.Good reliability: The structure of the dry contact is simple, the failure rate is low, and it is suitable for long-term stable operation.
5. Popular discussions on dry contacts in the past 10 days across the Internet
According to recent Internet hot spots, the following are hot topics and related data about dry contacts:
| topic | Discussion popularity | main focus |
|---|---|---|
| Application of dry contacts in smart homes | high | How to realize equipment linkage through dry contacts |
| Selection of dry contacts and wet contacts | in | Comparison of advantages and disadvantages in different scenarios |
| Troubleshooting Dry Contacts | in | Frequently asked questions and solutions |
6. Summary
As a simple and reliable switching signal device, dry contact plays an important role in the field of electrical control and automation. Through the introduction of this article, I believe readers will have a clearer understanding of the definition, characteristics and applications of dry contacts. In actual applications, the appropriate contact type should be selected according to specific needs to ensure the stability and safety of the system.
If you have other questions about dry contacts, please leave a message in the comment area to discuss!
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